Curable Resin Composition, Surface Protection Method, Temporary Fixation Method, and Separation Method

ABSTRACT

To provide an environmentally-friendly curable resin composition for surface protection, having a high adhesive strength and being capable of forming a protective film which will readily be removed in the film form without adhesive residue in water on a member to be processed, a photocurable adhesive using it, a method for temporarily fixing a member, and a method for removing a protective film. 
     A curable resin composition for surface protection, comprising (A) a polyfunctional (meth)acrylate, (B) a monofunctional (meth)acrylate, and (C) a resin having a cyclopentadiene skeleton. Further, a curable resin composition for surface protection, comprising (A) a polyfunctional (meth)acrylate, (B) a monofunctional (meth)acrylate, (C) a resin having a cyclopentadiene skeleton, and (D) a photopolymerization initiator. Still further, a curable resin composition for surface protection, comprising (A) a polyfunctional (meth)acrylate, (B) a monofunctional (meth)acrylate, (C) a resin having a cyclopentadiene skeleton, (D) a photopolymerization initiator, and (E) a polar organic solvent.

TECHNICAL FIELD

The present invention relates to a surface protective film to protect amember to be processed in processing of various members from e.g.cutting wastes, and a surface protective film (hereinafter sometimesreferred to as “protective film”) for temporary fixation to protect aportion which should not be painted or printed in painting or printingof a member to be processed with e.g. an ink. Further, it relates to acurable resin composition suitable for such a film and a method forprotecting the surface of a member to be processed by using an adhesivecomprising the curable resin composition.

More specifically, the present invention relates to a method forremoving a protective film covering a member in processing of members,and a photocurable adhesive suitable for such an application. Further,it relates to a method for temporarily fixing a member to be processed,which comprises bonding the member to be processed to a substrate,processing the member to be processed, and immersing the bonded portionin warm water to remove the cured product thereby to recover the memberto be processed.

BACKGROUND ART

In processing, particularly precision processing such as cutting,grinding or polishing of metal plates, molds, aluminum sashes, plasticplates, semiconductor wafers, circuit boards, ceramics, opticalcomponents such as glass and quartz, and electric and electroniccomponents such as sensors, a surface protective film to temporarilyprotect components has been widely used so as to prevent damage bycutting water, scars or contamination by e.g. cutting wastes, orbreakage, by covering an already processed surface of a member to beprocessed and a functional portion such as a circuit or a sensorportion. As such a surface protective film, a pressure-sensitiveadhesive sheet has been mainly used.

Further, in plating process employed for a circuit board such as aprinted-wiring board, a pressure-sensitive adhesive sheet cut into anoptional shape, which is a protective material to prevent contaminationby a plating liquid, has been used as a masking material to a portion onwhich plating is not required on a circuit.

Further, in addition to electric and electronic components, painting andvarious printings are conducted by various printing methods on variousindustrial products, such as tablets such as nameplates and logos,scales on measuring instruments and decorations. In a case where thereis a portion on which painting or printing is not required, apressure-sensitive adhesive sheet is bonded to that portion and thenpainting or printing is carried out.

However, in a case where a pressure-sensitive adhesive sheet is used asa protective film when a member to be processed is processed, along withdownsizing and miniaturization of components in recent years, thebonding operation is complicated and in addition, even a slightdisplacement of the bonding position may impair the yield or the designproperties of the products. When a component has recesses andprotrusions, the sheet cannot follow the recesses and protrusions and isremoved during processing, thus contaminating the member to be processedin some cases. In addition, when a pressure-sensitive adhesive sheetwhich has been cut to be fitted to the shape of the member to beprocessed is to be used, an expensive mold is required to cut the sheet,such being disadvantageous in view of cost.

In order to solve these problems, separately from a pressure-sensitiveadhesive sheet, a masking method has been studied, comprising coating asurface of a member to be processed with an ultraviolet-curablecomposition capable of being removed by a specific organic solvent oraqueous alkali solution by screen printing, followed by curing withultraviolet rays for covering (Patent Documents 1 to 3).

However, since the method employs an aqueous alkali solution or anorganic solvent, the cleaning process is complicated, and the method isproblematic in view of working environment. Further, in a case where thesurface of a member to be processed has fine irregularities, the organicsolvent cannot sufficiently infiltrate, whereby the protective filmcannot completely be removed, thus causing problems in the outerappearance of the member to be processed.

Further, making a semiconductor wafer or an optical component thin(hereinafter sometime referred to as “grinding”) has been carried out bybackgrinding wherein a circuit surface of the wafer or the opticalcomponent is protected with a surface protective sheet, and the backside opposite to the circuit surface is ground.

At present, the thickness of wafers is usually 150 μm at the industriallevel. However, further thinner wafers have been desired. In a casewhere a wafer is made thinner, a phenomenon such that the ground side(back side) has irregularities by the influence of the recesses andprotrusions on the circuit surface, i.e. back transfer of a circuitpattern is remarkable.

The reason why the back transfer occurs is explained as follows. Namely,a pressure-sensitive adhesive surface protective sheet presently usedhas limited capability to follow recesses and protrusions of a circuiton a semiconductor wafer. Accordingly, a gap (air pocket) is presentbetween the adhesive layer and the circuit surface, and the wafer is notdirectly supported by the adhesive (protective layer) at that region.When the wafer is made thin by grinding, at the scribe line (street) notsupported, the wafer moves in the vertical direction between circuitdies while the air pocket is compressed and resultingly, the wafer isnot ground in this region and becomes thicker than the other portion. Onthe other hand, in a case where there are hard protrusions such asbumps, the wafer is further ground and becomes thinner at such a regionthan the other portion resultingly.

The above phenomenon is not problematic when the thickness of thefinished wafer is 150 μm or more, but when the wafer is thinner than 100μm (particularly when the wafer is finished to have a thickness of 50 μmor below) or when protrusions on the wafer circuit surface such as bumpsare remarkably high (for example, 100 μm or more), not only thedeflective strength of the wafer will be remarkably lowered, but in aworse situation, the wafer may be even broken during grinding.

Further, when the wafer is ground to make it thin at a level of 50 μm,the cutout of the edge of the wafer or infiltration of the grindingwater into a space between the wafer and the surface protective layerare problematic. This is also due to insufficient adhesion of thesurface protective sheet to the edge of the wafer. Further, along withthe tendency to make the wafer thin, on a semiconductor wafer which has,on the circuit surface, protrusions of 100 μm or higher represented bybumps, typical grinding itself carried out by bonding a semiconductorsurface protective sheet is difficult.

A conventional surface protective sheet is usually a sheet comprising apolymer film material and an adhesive layer as a surface protectivelayer on the polymer film material. The adhesive is designed to have alow elastic modulus so as to follow the recesses and protrusions on thecircuit surface. However, if this tendency is too significant, a greatstress will be applied to the wafer when the sheet is removed by peelingfrom the wafer, thus leading to breakage. Accordingly, a protectivesheet which will be easily removed by energy rays has been developed,wherein the adhesive is cured by irradiating with energy rays such asultraviolet rays before peeling of the sheet to reduce the adhesiveforce between the wafer and the protective sheet. However, the adhesivelayer is too soft if it is uncured at the time of grinding, whereby thewafer may be broken during grinding.

Patent Document 4 discloses a wafer grinding method which comprisesbonding the above protective sheet which will be easily removed byenergy rays to a wafer on which a circuit is formed, curing the adhesivelayer with energy rays, and then carrying out backgrinding of the wafer.However, the adhesive, which is not a fluid, has insufficient capabilityto follow the recesses and protrusions on the wafer circuit surface.

Further, Patent Document 5 discloses a hot-melt type semiconductorsurface protective sheet. A hot-melt type sheet which is melted byheating at from 60 to 100° C. and shows fluidity, follows the recessesand protrusions on the circuit surface and exhibits excellent grindingproperties. However, this sheet is repeatedly melted every time thetemperature exceeds the melting point.

A semiconductor wafer after bonded to a protective sheet, usuallyundergoes heating in a step of bonding a film to be used to fix a chipi.e. a die attachment film (hereinafter sometimes referred to as “DAF”)or in a step of forming a metal film by sputtering in some cases.Resultingly, such a defect may occur that the protective sheet isre-melted in some cases.

Further, separately from the surface protective film, a method has beenstudied to protect a member to be processed from e.g. cutting wastesduring processing, by coating the surface of a member with anultraviolet-curable adhesive which is soluble in a specific organicsolvent, followed by curing with ultraviolet rays for covering. However,since an organic solvent is used, the cleaning step is complicated, andthere is a problem in view of working environment. Further, in the caseof fine recesses and protrusions, the organic solvent cannotsufficiently infiltrate to completely remove the protective film, thuscausing problems in the outer appearance of the member to be processed.

Patent Document 1: JP-A-59-051962

Patent Document 2: JP-A-01-234477

Patent Document 3: JP-A-03-139573

Patent Document 4: JP-A-11-026406

Patent Document 5: JP-A-2000-038556

DISCLOSURE OF THE INVENTION Objects to be Accomplished by the Invention

In processing, particularly precision processing such as cutting,grinding or polishing of metal plates, molds, aluminum sashes, plasticplates, semiconductor wafers, circuit boards, ceramics, opticalcomponents such as glass and quartz, and electric and electroniccomponents such as sensors, a curable composition suitable forprotecting an already processed surface of a member to be processed or afunctional portion such as a circuit or a sensor portion, frominfiltration of cutting water or from scars or contamination by e.g.cutting wastes, and a removing method excellent in workability from theenvironmental viewpoint without adhesive residue, in removal of thecovering protective film from the member to be processed afterprocessing, have been desired.

Further, in order to improve the dimensional accuracy of a member aftercutting, a photocurable adhesive which is hydrophobic, which has highadhesive strength and which is excellent in releasability in water, hasbeen desired. Particularly, in a case where a semiconductor wafer, anoptical component or the like is made thin by backgrinding, aphotocurable adhesive having the above properties, which protects acircuit surface of a wafer or a surface which should not be processed ofan optical component, has been eagerly desired.

Further, a protective film which protects, in processing of theabove-exemplified optical components or electric or electroniccomponents such as sensors, such a member or the surface of a memberfrom infiltration of cutting water or from scars or contamination bye.g. cutting wastes, a protective film which prevents contamination by aplating liquid used for a circuit board such as a printed wiring board,and further, a curable resin composition for surface protection withfavorable workability, as a temporary protective film suitable formasking at the time of painting or printing of various industrialproducts such as tablets such as nameplates and logos, scales onmeasuring instruments and decorations, in addition to electric orelectronic components, have been desired.

Means to Accomplish the Objects

The present inventors have conducted studies to achieve the aboveobjects and as a result, made the following findings and accomplishedthe present invention.

(a) The above objects are achieved by a method wherein a protective filmmade of a favorable curable resin composition which is a material havingsufficient capability to follow the recesses and protrusions of a metalplate, a semiconductor wafer or an optical component, and which hassufficient rigidity as a protective film for processing and has highadhesive strength, is provided on a member to be processed, the memberto be processed is processed, a sheet is bonded to the surface of themember to be processed and/or the protective film, and the member to beprocessed is separated from the protective film and the sheet, or theprotective sheet is separated from the member to be processed and thesheet.

(b) The above object is achieved by a curable resin compositioncomprising a (meth)acrylate monomer and a resin having a cyclopentadieneskeleton as components, which is a material having sufficient capabilityto follow the recesses and protrusions on a circuit surface of a waferor an optical component and which is a composition having sufficientrigidity as a support at the time of grinding.

(c) A curable resin composition comprising a specific (meth)acrylatemonomer is suitable as a surface protective film for processing of amember to be processed, such a composition having a specific viscositymakes application of screen printing possible, and in addition, when aprotective film made of such a curable resin composition is used, amethod for protecting the surface of a member to be processed, which iscapable of preventing scars or stain during processing of the member tobe processed and with which no surface protective film will remainunremoved, can be provided.

The present invention provides the following:

(1) A curable resin composition for surface protection, comprising (A) apolyfunctional (meth)acrylate, (B) a monofunctional (meth)acrylate, and(C) a resin having a cyclopentadiene skeleton.(2) A curable resin composition for surface protection, comprising (A) apolyfunctional (meth)acrylate, (B) a monofunctional (meth)acrylate, (C)a resin having a cyclopentadiene skeleton, and (D) a photopolymerizationinitiator.(3) A curable resin composition for surface protection, comprising (A) apolyfunctional (meth)acrylate, (B) a monofunctional (meth)acrylate, (C)a resin having a cyclopentadiene skeleton, (D) a photopolymerizationinitiator, and (E) a polar organic solvent.(4) The curable resin composition for surface protection according toany one of the above (1) to (3), wherein (C) has an ester group or ahydroxyl group in its molecule.(5) A curable resin composition for surface protection, comprising (F) a(meth)acrylate having at least one (meth)acryloyl group at the terminalor in the side chain of its molecule and having a molecular weight of atleast 500, (G) a (meth)acrylate other than (F), and (D) aphotopolymerization initiator.(6) The curable resin composition for surface protection according tothe above (5), wherein (F) is at least one member selected from thegroup consisting of polybutadiene, polyisoprene, and a hydrogenatedproduct of polybutadiene or polyisoprene.(7) The curable resin composition for surface protection according tothe above (5) or (6), which further contains (H) an inorganic filler.(8) The curable resin composition for surface protection according tothe above (7), wherein (H) is silica.(9) The curable resin composition for surface protection according toany one of the above (1) to (8), wherein each of (A), (B), (F) and (G)is a hydrophobic (meth)acrylate.(10) The curable resin composition for surface protection according tothe above (1), which comprises from 1 to 50 parts by mass of (A), from 5to 95 parts by mass of (B), and from 0.1 to 50 parts by mass of (C).(11) The curable resin composition for surface protection according tothe above (2), which comprises from 1 to 50 parts by mass of (A), from 5to 95 parts by mass of (B), from 0.1 to 50 parts by mass of (C), andfrom 0.1 to 20 parts by mass of (D).(12) The curable resin composition for surface protection according tothe above (3), which comprises from 1 to 50 parts by mass of (A), from 5to 95 parts by mass of (B), from 0.1 to 50 parts by mass of (C), from0.1 to 20 parts by mass of (D), and from 0.5 to 10 parts by mass of (E).(13) The curable resin composition for surface protection according tothe above (5), which comprises from 20 to 90 parts by mass of (F), from10 to 80 parts by mass of (G), and from 0.1 to 20 parts by mass of (D).(14) The curable resin composition for surface protection according toany one of the above (5) to (9) and (13), which has a viscosity of atleast 5,000 mPa·s.(15) An adhesive comprising the curable resin composition for surfaceprotection as defined in any one of the above (1) to (4), (9), (10),(11), (12) and (13).(16) A member to be processed, having a cured product of the curableresin composition for surface protection as defined in any one of theabove (1) to (14) provided on its surface.(17) A method for protecting the surface of a member to be processed,which comprises providing a protective film made of a cured product ofthe curable resin composition for surface protection as defined in anyone of the above (1) to (14), on the surface of the member to beprocessed, processing the member to be processed, and removing theprotective film from the member to be processed.(18) The method for protecting the surface of a member to be processedaccording to the above (17), wherein when the protective film is removedfrom the member to be processed, at least the protective film isimmersed in warm water of at most 90° C.(19) The method for protecting the surface of a member to be processedaccording the above (17) or (18), wherein the protective film isprovided on the surface of a member to be processed by screen printing.(20) A method for temporarily fixing a member to be processed, whichcomprises bonding the member to be processed to a substrate by means ofthe curable resin composition for surface protection as defined in anyone of the above (1) to (14), curing the composition, processing themember to be processed, and immersing the processed member in warm waterof at most 90° C., thereby to remove a cured product of the curableresin composition for surface protection.(21) A method for removing a protective film, which comprises providinga protective film made of the curable resin composition for surfaceprotection as defined in any one of the above (1) to (14) on the surfaceof a member to be processed, processing the member to be processed, andremoving the protective film from the member to be processed, wherein asheet is bonded to the surface of the member to be processed and/or theprotective film, and the member to be processed is separated from theprotective film and the sheet, or the protective film is separated fromthe member to be processed and the sheet.(22) The method for removing a protective film according to the above(21), wherein when the member to be processed is separated from theprotective film and the sheet, at least the protective film is broughtinto contact with warm water.(23) The method for removing a protective film according to the above(21) or (22), wherein the sheet bonded to the surface of the member tobe processed and/or the protective film, is a pressure-sensitiveadhesive sheet comprising a substrate and an adhesive layer formed onthe substrate.(24) The method for removing a protective film according to the above(23), wherein the adhesive layer of the sheet is an adhesive curablewith energy rays.(25) The method for removing a protective film according to the above(23) or (24), wherein the protective film and the sheet adhesive layerare combined by irradiating the sheet with energy rays.

EFFECTS OF THE INVENTION

The method for removing a protective film of the present inventioncontributes to labor saving, energy saving and reduction in operationtime as compared with a conventional hot-melt adhesive, since aprotective film made of a curable resin composition is photocurable dueto its composition, i.e. it is cured by active energy rays such asvisible light or ultraviolet rays.

Further, the protective film made of the curable resin composition showsa high adhesive strength without being influenced by e.g. cutting waterused at the time of processing, whereby it hardly causes displacementduring processing of a component, and it is capable of protecting thecomponent from infiltration of cutting water or from scars orcontamination by e.g. cutting wastes. In addition, with respect to theremoval of the protective film from the member to be processed afterprocessing, by bonding a sheet to the surface of the member to beprocessed and/or the protective film, the removal is carried out easilywithout adhesive residue with excellent workability.

Further, when a protective film having a specific composition is used,by bringing the protective film into contact with warm water of at least30° C., particularly warm water of at most 90° C., the adhesive strengthwill be lowered, and the bonding force between members or between amember and a jig will decrease, whereby the member will be readilyrecovered. Accordingly, it is not necessary to use an organic solventwhich is expensive, which is highly flammable and which generates a gasharmful to the human body, as in the case of an adhesive used for aconventional surface protective film.

Further, the method is excellent in workability since the sheet used isa pressure-sensitive adhesive sheet comprising an adhesive layer formedon a substrate. Particularly in a case where the adhesive layer of thesheet is an adhesive curable with energy rays, the adhesive force willdecrease by irradiation with energy rays. Further, since the protectivefilm and the sheet covering the member to be processed are removed ascombined, the member will be recovered without complexity.

Further, a curable resin composition having a specific preferredcomposition provides excellent workability since its cured productswells when brought into contact with warm water of at most 90° C.,whereby it can be recovered in the form of a film from the member.

The curable resin composition for surface protection of the presentinvention contributes to labor saving, energy saving and reduction inoperation time since it has a viscosity with which screen printing isapplicable, in the preferred embodiments.

BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, the curable resin composition forming aprotective film comprises (A) a polyfunctional (meth)acrylate, (B) amonofunctional (meth)acrylate, (C) a resin having a cyclopentadieneskeleton, and (D) a photopolymerization initiator.

(A) to be used for the curable resin composition is a polyfunctional(meth)acrylate oligomer/polymer having at least two (meth)acryloylgroups at the terminals or in the side chains of the oligomer/polymer,or a monomer having at least two (meth)acryloyl groups.

As examples thereof, the polyfunctional (meth)acrylate oligomer/polymermay, for example, be 1,2-polybutadiene-terminated urethane(meth)acrylate (e.g. “TE-2000” or “TEA-1000”, manufactured by NIPPONSODA CO., LTD.), a hydrogenated product of the above acrylate (e.g.“TEAI-1000” manufactured by NIPPON SODA CO., LTD.),1,4-polybutadiene-terminated urethane (meth)acrylate (e.g. “BAC-45”,manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.),polyisoprene-terminated (meth)acrylate, polyester urethane(meth)acrylate, polyether urethane (meth)acrylate, polyester(meth)acrylate, or bis-A type epoxy (meth)acrylate (e.g. “Biscoat #540”manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD., or “Biscoat VR-77”manufactured by SHOWA HIGHPOLYMER CO., LTD.).

Further, among monomers having at least two (meth)acryloyl groups, abifunctional (meth)acrylate monomer may, for example, be 1,3-butyleneglycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexadioldi(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycoldi(meth)acrylate, dicyclopentanyl di(meth)acrylate,2-ethyl-2-butyl-propanediol (meth)acrylate, neopentyl glycol-modifiedtrimethylol propane di(meth)acrylate, stearic acid-modifiedpentaerythritol diacrylate, polypropylene glycol di(meth)acrylate,2,2-bis(4-(meth)acryloxy diethoxyphenyl)propane,2,2-bis(4-(meth)acryloxy propoxyphenyl)propane or2,2-bis(4-(meth)acryloxy tetraethoxyphenyl)propane.

A trifunctional (meth)acrylate monomer may, for example, betrimethylolpropane tri(meth)acrylate ortris[(meth)acryloxyethyl]isocyanurate.

A tetrafunctional or higher-functional (meth)acrylate monomer may, forexample, be dimethylolpropane tetra(meth)acrylate, pentaerythritoltetra(meth)acrylate, pentaerythritolethoxy tetra(meth)acrylate,dipentaerythritol penta(meth)acrylate or dipentaerythritolhexa(meth)acrylate.

(A) to be used for the curable resin composition is more preferablyhydrophobic. If it is water-soluble, a protective film made of thecurable resin composition may swell by cutting water during processing,to cause displacement or removing, infiltration of cutting water, scarsor contamination by e.g. cutting wastes and degrade machining accuracy,such being undesirable. However, it may be hydrophilic unless theprotective film made of the curable resin composition significantlyswells or dissolves in part with water.

The amount of (A) to be used for the curable resin composition ispreferably from 1 to 50 parts by mass, more preferably from 5 to 40parts by mass, per 100 parts by mass of the total amount of (A) and (B).When it is at least 1 part by mass, the removability will not decrease,or the protective film made of the curable resin composition will remainin the film form, and when the amount is at most 50 parts by mass, theinitial adhesion will not decrease due to too significant shrinkage oncuring.

(B) to be used for the curable resin composition may, for example, bemethyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate,butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl(meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl(meth)acrylate, phenyl (meth)acrylate, cyclohexyl (meth)acrylate,dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate,dicyclopentenyloxyethyl (meth)acrylate, isobornyl (meth)acrylate,methoxylated cyclodecatriene (meth)acrylate, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl(meth)acrylate, 4-hydroxybutyl (meth)acrylate, tetrahydrofurfuryl(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glycidyl(meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate,3-chloro-2-hydroxypropyl (meth)acrylate, N,N-dimethylaminoethyl(meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, t-butylaminoethyl(meth)acrylate, ethoxycarbonylmethyl (meth)acrylate, phenol ethyleneoxide-modified acrylate, phenol(2-mol ethylene oxide-modified) acrylate,phenol(4-mol ethylene oxide-modified) acrylate, paracumylphenol ethyleneoxide-modified acrylate, nonylphenol ethylene oxide-modified acrylate,nonylphenol (4-mol ethylene oxide-modified) acrylate, nonylphenol (8-molethylene oxide-modified) acrylate, nonylphenol (2.5-mol propyleneoxide-modified) acrylate, 2-ethylhexyl carbitol acrylate, ethyleneoxide-modified phthalic acid (meth)acrylate, ethylene oxide-modifiedsuccinic acid (meth)acrylate, trifluoroethyl (meth)acrylate, acrylicacid, methacrylic acid, maleic acid, fumaric acid,ω-carboxy-polycaprolactone mono(meth)acrylate, phthalic acidmonohydroxyethyl (meth)acrylate, (meth)acrylic acid dimer,β-(meth)acroyloxyethyl hydrogen succinate, or n-(meth)acryloyloxyalkylhexahydrophthalimide.

Like (A), (B) to be used for the curable resin composition is morepreferably hydrophobic. If it is water-soluble, the protective film madeof the curable resin composition may swell by cutting water duringprocessing, to cause displacement or removing, infiltration of cuttingwater, scars or contamination by e.g. cutting wastes, and degrademachining accuracy, such being undesirable. However, it may behydrophilic unless the protective film made of the curable resincomposition significantly swells or dissolves in part with water.

The amount of (B) to be used for the curable resin composition ispreferably from 5 to 95 parts by mass, more preferably from 10 to 80parts by mass, per 100 parts by mass of the total amount of (A) and (B).When it is at least 5 parts by mass, sufficient initial adhesion will beobtained, and when it is at most 95 parts by mass, sufficientreleasability will be obtained, and a protective film made of thecurable resin composition will be obtained in the film form.

The adhesion to a metal surface can be further improved by using, incombination with the above blend composition of (A) and (B), a phosphatehaving a vinyl group or a (meth)acryl group, such as(meth)acryloyloxyethyl acid phosphate, dibutyl 2-(meth)acryloyloxyethylacid phosphate, dioctyl 2-(meth)acryloyloxyethyl phosphate, diphenyl2-(meth)acryloyloxyethyl phosphate or (meth)acryloyloxyethylpolyethylene glycol acid phosphate.

Further, in the present invention, a curable resin composition forsurface protection comprising (F), (G) and (D) a photopolymerizationinitiator may suitably be used, where the (meth)acrylate is classifiedinto (F) a (meth)acrylate having at least one (meth)acryloyl group atthe terminal or in the side chain of its molecule and having a molecularweight of at least 500, and (G) a (meth)acrylate other than (F).

Here, (F) may be a commercially available polyfunctional (meth)acrylateoligomer/polymer exemplified for the above (A).

The molecular weight of (F) is selected to be at least 500 with a viewto obtaining a viscosity with which screen printing is possible. It isnot necessary to define the upper limit with a technological viewpoint,but the curable resin composition for surface protection is preferablyliquid from the viewpoint of workability, and further, preferred is onehaving a molecular weight of at most 100,000 from the reason ofsolubility in the other (meth)acrylate monomer. The molecular weight of(F) is more preferably from 1,000 to 50,000.

(F) is preferably at least one member selected from the group consistingof polybutadiene, polyisoprene and hydrogenated products of the formertwo, whereby the removal nature of the cured product of the curableresin composition for surface protection from the adherend (hereinafterreferred to simply as “the removability”) will be improved when thecured product is immersed in warm water.

In the present invention, the addition amount of (F) is preferably from20 to 90 parts by mass, more preferably from 25 to 85 parts by mass, per100 parts by mass of the total amount of (F) and (G). When it is atleast 20 parts by mass, sufficient removability will be obtained, and aviscosity with which screen printing is applicable can be secured.Further, if it is at most 90 parts by mass, workability will notdecrease due to the viscosity increase.

(F) is preferably hydrophobic. If it is water-soluble, the cured productof the curable resin composition for surface protection may swell ordissolve in part during cutting, to cause displacement and degrademachining accuracy, such being undesirable. However, it may behydrophilic unless the cured product of the curable resin compositionfor surface protection significantly swells or dissolves in part withwater.

Further, (G) may be the monofunctional (meth)acrylate monomerexemplified for the above (B), or the polyfunctional (meth)acrylatemonomer (bifunctional, trifunctional or tetrafunctional (meth)acrylatemonomer) exemplified for the above (A).

The addition amount of (G) to be used in the present invention ispreferably from 10 to 80 parts by mass, more preferably from 15 to 75parts by mass, per 100 parts by mass of the total amount of (F) and (G).If it is less than 10 parts by mass, the initial adhesion may decrease,and if it exceeds 80 parts by mass, the releasability may decrease.

The adhesion to a metal surface can be further improved by using, incombination with the above blend composition of (F) and (G), a phosphatehaving a vinyl group or a (meth)acryl group, such as(meth)acryloyloxyethyl acid phosphate, dibutyl 2-(meth)acryloyloxyethylacid phosphate, dioctyl 2-(meth)acryloyloxyethyl phosphate, diphenyl2-(meth)acryloyloxyethyl phosphate or (meth)acryloyloxyethylpolyethylene glycol acid phosphate.

Like (F), (G) to be used in the present invention is more preferablyhydrophobic. If it is water-soluble, the protective film made of thecurable resin composition for surface protection may swell by cuttingwater during processing, to cause displacement or removing, infiltrationof cutting water, scars or contamination by e.g. cutting wastes, anddegrade machining accuracy, such being undesirable. However, it may behydrophilic unless the protective film made of the curable resincomposition for surface protection significantly swells or dissolves inpart with water.

The surface curing property can be further improved by using, incombination with the curable resin composition for surface protection ofthe present invention, (C) a resin having a cyclopentadiene skeleton.

(C) may, for example, be a petroleum resin produced from cyclopentadieneextracted from a CS fraction as the chief material. Specifically, e.g.“Quintone 1700”, “Quintone 1500” or “Quintone 1325”, manufactured byZEON CORPORATION may, for example, be mentioned.

(C) to be used for the curable resin composition may be any resin solong as it has a cyclopentadiene skeleton, but preferred is one having asoftening point of from 50° C. to 200° C., and more preferred is onehaving a number average molecular weight (Mn) of from 300 to 600 in viewof solubility.

The amount of (C) to be used for the curable resin composition ispreferably from 0.5 to 50 parts by mass, more preferably from 1 to 40parts by mass per 100 parts by mass of the total amount of (A) and (B).When it is at least 0.5 part by mass, a film will be formed withoutadhesive residue, and when it is at most 50 parts by mass, sufficientadhesion will be obtained.

(D) to be used for the curable resin composition is incorporated inorder to effect sensitization with active energy rays such as visiblelight or ultraviolet rays to enhance the photocuring property of thecurable resin composition, and can be one of various knownphotopolymerization initiators.

Specifically, it may, for example, be benzophenone or its derivative;benzyl or its derivative; anthraquinone or its derivative; benzoin or abenzoin derivative such as benzoin methyl ether, benzoin ethyl ether,benzoin propyl ether, benzoin isobutyl ether or benzyl dimethyl ketal;an acetophenone derivative such as diethoxyacetophenone, or4-t-butyltrichloroacetophenone; 2-dimethylaminoethyl benzoate,p-dimethylaminoethyl benzoate, diphenyl disulfide, thioxanthone or theirderivatives; camphor quinone or a camphor quinone derivative such as7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxylic acid,7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxy-2-bromoethylester,7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxy-2-methyl ester or7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carboxylic acid chloride;an α-amino alkylphenone derivative such as2-methyl-1-[4-(methylthio)phenyl]-2-morpholino propan-1-one or2-benzyl-2-dimethylamino-1-(4-morpholino phenyl)-butanone-1; or an acylphosphine oxide derivative such as benzoyl diphenyl phosphine oxide,2,4,6-trimethyl benzoyl diphenyl phosphine oxide, benzoyldiethoxyphosphine oxide, 2,4,6-trimethyl benzoyl dimethoxyphenylphosphine oxide or 2,4,6-trimethyl benzoyl diethoxyphenyl phosphineoxide. The photopolymerization initiators can be used alone or incombination as a mixture of two or more of them.

The addition amount of (D) to be used for the curable resin compositionis preferably from 0.1 to 20 parts by mass, more preferably from 3 to 20parts by mass, per 100 parts by mass of the total amount of (A) and (B),or (F) and (G). When the amount is at least 0.1 part by mass, it ispossible to obtain the effect of promoting the curing. On the otherhand, when the amount is at most 20 parts by mass, a sufficient curingrate can be obtained. A more preferred embodiment is such that (D) isadded by at least 3 parts by mass, which is further preferred in thatthe composition becomes curable regardless of the light irradiationlevel, the crosslinking degree of the cured product of the curable resincomposition becomes higher, no displacement occurs during cutting, andthe removability is improved.

Further, it is certainly possible to develop a phenomenon such that theadhesive strength of the protective film made of the curable resincomposition is lowered when it swells by contact with warm water, byusing (E) a polar organic solvent in combination with the curable resincomposition comprising (A), (B), (C) and (D), or (F), (G) and (D), orthe like.

(E) preferably has a boiling point of at least 50° C. and at most 130°C. When a polar organic solvent having a boiling point within the aboverange is selected, it is more certainly possible to develop a phenomenonsuch that the adhesive strength of the curable resin composition aftercuring is lowered by contact with warm water, such being desirable.

Such a polar organic solvent may, for example, be an alcohol, a ketoneor an ester. As a result of a study by the present inventors, an alcoholis preferably selected among them.

The alcohol may, for example, be methanol, ethanol, n-propanol,isopropanol, n-butanol, isobutanol, secondary butanol, tertiary butanol,n-amyl alcohol, isoamyl alcohol or 2-ethyl butyl alcohol.

Among them, methanol, ethanol, n-propanol, isopropanol, n-butanol,isobutanol, secondary butanol or tertiary butanol, which has a boilingpoint of not higher than 120° C., is preferred, and methanol, ethanol,isopropanol or n-butanol is more preferred. Particularly preferred isethanol or isopropanol, which has a boiling point of not higher than100° C., which emits little odor and which is not designated as adeleterious substance.

The addition amount of (E) is preferably from 0.5 to 30 parts by mass,more preferably from 1 to 20 parts by mass, per 100 parts by mass of thetotal amount of (A) and (B), or (F) and (G) in the curable resincomposition. When it is at least 0.5 part by mass, releasability will besecured, and when it is at most 30 parts by mass, the initial adhesionwill not decrease, and the cured product of the curable resincomposition will be removed in the is film form.

In order to improve the storage stability, the curable resin compositionof the present invention may contain a small amount of a polymerizationinhibitor. The polymerization inhibitor may, for example, be methylhydroquinone, hydroquinone,2,2-methylene-bis(4-methyl-6-tertiary-butylphenol), catechol,hydroquinone monomethyl ether, monotertiary butyl hydroquinone,2,5-ditertiary butyl hydroquinone, p-benzoquinone,2,5-diphenyl-p-benzoquinone, 2,5-ditertiary-butyl-p-benzoquinone, picricacid, citric acid, phenothiazine, tertiary-butyl catechol,2-butyl-4-hydroxyanisole or 2,6-ditertiary-butyl-p-cresol.

The amount of the polymerization inhibitor to be used is preferably from0.001 to 3 parts by mass, more preferably from 0.01 to 2 parts by massper 100 parts by mass of the total amount of (A) and (B), or (F) and (G)in the curable resin composition. When the amount is at least 0.001 partby mass, the storage stability will not decrease, and when it is at most3 parts by mass, the adhesion will not decrease, and the composition canbe prevented from being uncured.

To the curable resin composition of the present invention, (H) aninorganic filler may be added in addition to the above respectivecomponents depending upon the application, particularly when it is usedfor e.g. screen printing.

(H) may, for example, be an oxide such as spherical alumina, crushedalumina, magnesium oxide, beryllium oxide or titanium oxide, a nitridesuch as boron nitride, silicon nitride or aluminum nitride, a carbidesuch as silicon carbide, a hydrated metal such as aluminum hydroxide ormagnesium hydroxide, a metal filler such as copper, silver, iron,aluminum or nickel, a metal alloy filler such as titanium, a carbidetype filler such as diamond or carbon, silica such as quartz, quartzglass, fused silica, spherical silica or fumed silica, silica sand,fersmanite, clay, talc, calcium carbonate, glass beads or shiras baloon.These inorganic fillers may be used alone or in combination of two ormore of them. Among these inorganic fillers, preferred is silicaconsidering photocuring property of the curable resin composition forsurface protection, and more preferred is dry method silica consideringscreen printability, which is easily available.

The dry method silica is, among silica powders, common name white carbonsuch as a crystalline silica powder, a fused silica powder, a sphericalsilica powder and a fumed silica powder, a silica produced by subjectingsilicon tetrachloride to heat decomposition in the presence of hydrogenand oxygen at a high temperature at a level of 1,000° C. In the drymethod silica, silanol groups are exposed to the surface of theparticles since the silica interior structure is stable.

Further, in the present invention, the dry method silica may be asurface-treated silica obtained by making silanol groups present on thesurface of silica be hydrophobic by reaction with an organic siliconhalide or an alcohol, so as to modify the surface and to improvedispersibility. Such a dry method silica may, for example, be “AEROSIL130”, “AEROSIL 200”, “AEROSIL 300”, “AEROSIL 380”, “AEROSIL R972” (eachmanufactured by NIPPON AEROSIL CO., LTD.), “Cab-O—Sil” (manufactured byG.L. Cabot Corp.), “DC Fine Silica” (manufactured by Dow Corning) or“Fransil 251” (manufactured by Farnsol).

The above dry method silica is used for general purpose, in a case ofcoating with a coating composition or an adhesive, to increase thestructural viscosity of the liquid to prevent dripping, and addition ofthe dry method silica makes it easy to achieve a viscosity with whichscreen printing is applicable.

The viscosity of the curable resin composition for surface protection ofthe present invention is preferably at least 5,000 mPa·s. When it is atleast 5,000 mPa·s, no dripping will occur, and a favorable protectivefilm will be obtained. It is more preferably at least 10,000 mPa·s,whereby a more favorable protective film will be obtained by screenprinting. Further, the upper limit of the viscosity is suitably selecteddepending upon the purpose of use of the curable resin composition, andit is preferably at most 2,000,000 mPa·s in the case of screen printingand it is preferably at most 100,000 mPa·s in the case of e.g. brushcoating.

Further, the curable resin composition for surface protection of thepresent invention may contain an additive, such as an elastomer ofvarious type, e.g., acryl rubber, urethane rubber oracrylonitrile-butadiene-styrene rubber, a solvent, an extender, areinforcing material, a plasticizer, a thickener, a dye, a pigment, aflame retardant, a silane coupling agent or a surfactant, within a rangenot to impair the object of the present invention.

The sheet to be used in the present invention is one comprising asubstrate and an adhesive layer of e.g. a rubber type adhesive such asnatural rubber, styrene-butadiene rubber, isobutyrene rubber, isoprenerubber, a styrene-isoprene rubber block copolymer or a styrene-butyreneblock copolymer or an acrylic type, a silicone type, a polyurethane typeor a polyvinylether type adhesive, formed on the substrate e.g. bycoating or impregnation, the substrate being e.g. paper such as craftpaper, Japanese paper or crepe paper, cloth such as a single or mixedwoven fabric of e.g. rayon, cotton, glass, polyester or vinylon, clothmade of e.g. spun polypropylene fibers, or a non-woven fabric of e.g.rayon, polypropylene, aromatic polyamide, polyester or glass, a plasticfilm of e.g. cellophane, acetate, polyolefin such as polyvinyl chloride,polyethylene or polypropylene, polyester, polytetrafluoroethylene,polyethylene terephthalate (PET) or polyimide, a rubber sheet of asingle substance or a mixture of e.g. natural rubber, styrene butadienerubber, butyrene rubber or polychloroprene rubber, a foam of e.g.polyurethane, polyethylene, butyl rubber, polystyrene, polychloroprenerubber or acrylic rubber or a metal foil of e.g. aluminum, copper orstainless steel. So-called a marking film tape such as a label or asticker, an adhesive film, an adhesive sheet or an adhesive tape may,for example, be used.

Further, the shape and the form are not limited so long as it is asheet-shaped one which can be bonded to the surface of the member to beprocessed, such as a thermosetting adhesive sheet comprising the abovesupport coated with an epoxy type, polyimide type or polyurethane typeresin.

Among the sheets to be used in the present invention, preferred is apressure-sensitive adhesive sheet comprising the above substrate and apressure-sensitive adhesive layer of e.g. an acrylic copolymer, in viewof easiness of bonding operation.

Further, the adhesive layer of the above sheet preferably comprises anadhesive curable with energy rays, whereby the sheet will be easilyremoved from the member to be processed, since the adhesive force willbe significantly reduced after irradiation with energy rays.Specifically, the sheet employing such an adhesive curable with energyrays may, for example, be a dicing tape or a backgrinding tape to beused as an adhesive for fixing, at the time of grinding and/or cutting,e.g. a circuit board such as a silicon wafer or a glass-reinforced epoxyresin or a ceramic which employs, as the substrate, polyvinyl chlorideor polyolefin which is relatively stretchable.

The above sheet is such a sheet that the substrate is expanded andpushed up upon irradiation with energy rays, and the member to beprocessed such as an aimed chip is picked up and is thereby separated.For example, the member to be processed is coated with a protectivefilm, and a dicing tape as an adhesive for fixation is bonded to thesurface of the member to be processed coated with the protective film,and the member to be processed is cut by a cutting apparatus such as adicer. Then, energy rays are applied to weaken the adhesive force, thetape is expanded, and the member to be processed is picked up.

The adhesive curable with energy rays comprises, as the main components,a pressure-sensitive adhesive made of an acrylic copolymer and acompound polymerizable by energy rays, and accordingly such an effectwill also be obtained that it is not troublesome to recover memberssince the sheet can be removed together with the protective film made ofthe curable resin composition.

The sheet may be preliminarily bonded to the protective film beforeprocessing, or it may be bonded to the protective film after processing,depending upon the manner of processing.

In the present invention, after the above sheet is bonded to the memberto be processed and/or the protective film, an appropriate outer forceis applied to e.g. the member to be processed, the protective film andthe sheet, whereby the member to be processed can be separated from theprotective film and the sheet, or the protective film can be separatedfrom the member to be processed and the sheet.

The present invention provides a method for removing a protective film,which comprises providing a protective film made of a curable resincomposition on the surface of a member to be processed, processing themember to be processed and removing the protective film from the memberto be processed, wherein a sheet is bonded to the surface of the memberto be processed and/or the protective film, and the member to beprocessed is separated from the protective film and the sheet, or theprotective film is separated from the member to be processed and thesheet.

According to the preferred embodiment of the present invention, toseparate the member to be processed from the protective film and thesheet, at least the protective film is brought into contact with warmwater so that the protective film will swell and be softened. Thus, in acase where a sheet is bonded to the protective film, the protective filmwill be combined with the sheet and easily removed, and the member to beprocessed will easily be recovered, such being excellent in workability.

Further, the present invention provides the following method fortemporarily fixing a member to be processed.

Namely, a method for temporarily fixing a member, which comprisesbonding a member to be processed to a substrate by means of the curableresin composition which loses the adhesive strength upon contact withwarm water of at most 90° C., curing the curable resin composition totemporarily fix the member, then processing the temporarily fixed memberand immersing the processed member together with the substrate ifrequired in warm water to remove the cured adhesive, whereby variousmembers such as optical members can be processed with high machiningaccuracy, without use of an organic solvent.

According to a preferred embodiment of the present invention, at thetime of removing the member, the cured product of the curable resincomposition is brought into contact with warm water of at most 90° C. toswell and is removed in the form of a film from the member, whereby itis possible to obtain an effect of excellent workability.

In the temporary fixation method of the present invention, by the use ofan adhesive made of the curable resin composition of the presentinvention, it is possible to certainly obtain the above effect.

In the present invention, use of warm water appropriately heated to atmost 90° C. is preferred in terms of productivity because theremovability is thereby achieved in a short period of time. Thetemperature of the warm water is from 30 to 90° C., preferably from 40to 80° C.

Use of warm water is preferred because the protective film made of thecurable resin composition will swell or be softened a little in a shortperiod of time, whereby after bonding the sheet to the protective film,the protective film in the form of a film is combined with the sheet andremoved together.

The method of bringing the protective film and warm water into contactis not particularly limited. Either method of immersing the member to beprocessed having the protective film provided thereon or only theprotective film portion in warm water, and then bonding a sheet, or amethod of immersing a member to be processed having the protective filmprovided thereon and having a sheet bonded thereto, in warm water, maybe employed. By removing the sheet after immersion in warm water, themember to be processed will be more easily separated from the protectivefilm and the sheet, or the protective film will be more easily separatedfrom the member to be processed and the sheet.

In the present invention, use of a protective film made of a curableresin composition comprising (A) a polyfunctional (meth)acrylate, (B) amonofunctional (meth)acrylate, (C) a resin having a cyclopentadieneskeleton and (D) a photopolymerization initiator, is preferred becauseit is possible to certainly obtain the effect of the invention. Further,use of a protective film made of a curable resin composition furthercontaining (E) a polar organic solvent is more preferred.

By bringing the protective film made of the curable resin composition ofthe present invention into contact with warm water, the residual stressin curing is released, whereby the adhesive strength will be reduced,and particularly the vapor pressure of (E) a polar organic solventfunctions together with a removing force thereby enabling the protectivefilm to be easily removed in the form of a film from the member to beprocessed.

In the present invention, the material of the member to be temporarilyfixed and the substrate is not particularly limited, and in a case wherethe adhesive is an ultraviolet-curable adhesive, the member and thesubstrate are preferably made of a UV transmitting material. Examples ofsuch materials include crystal members, glass members, plastic membersand wafers.

The temporary fixation method of the present invention can be applied totemporary fixation in processing of e.g. glass lenses, plastic lenses,wafers and optical disks.

With respect to the method of using the adhesive in the temporaryfixation method, assuming a case where a photocurable adhesive is usedas the adhesive, for example, an appropriate amount of the adhesive isapplied to one of or both sides of the member to be fixed or thesubstrate, and visible light or ultraviolet rays are applied to theadhesive to the member or the substrate, to cure the photocurableadhesive to temporarily fix the member.

Then, the temporarily fixed member is subjected to processing such ascutting, grinding, polishing or drilling into a desired shape, and thenthe member is immersed in water preferably warm water, whereby the curedproduct of the adhesive can be removed from the member.

Further, the present invention provides a method for protecting thesurface of a member to be processed, which comprises covering thesurface of the member to be processed with the curable resincomposition, curing the composition, processing the member to beprocessed, and immersing the processed member in a warm water of at most90° C. thereby to remove a cured product of the curable resincomposition. Namely, by coating the unprocessed surface of the member tobe processed with the curable resin composition and curding thecomposition, it is possible to prevent the surface from being stainedduring the processing or to prevent chipping.

Further, the present invention provides a method for protecting thesurface of a member to be processed, which comprises providing aprotective film made of a curable resin composition for surfaceprotection on the surface of the member to be processed, processing themember to be processed, and removing the protective film from the memberto be processed.

By the above method, e.g. a ceramic, glass, an optical component such asquartz or an electric or electronic component such as a sensor, isprotected from infiltration of cutting water during processing or fromscars or contamination of the member to be processed by e.g. cuttingwastes. Further, the protective film functions as a protective filmsuitable to prevent contamination by a plating liquid to be used for acircuit board such as a printed wiring board, or for masking at the timeof painting or printing of various tablets such as nameplates or logos,scales on measuring instruments or decorations.

As a method of providing a protective film on the surface of the memberto be processed, an optional application method may be employed, such asbrush coating, various coating methods, screen printing, flexographicprinting, spraying, potting or dipping. Among them, it is preferred toemploy screen printing.

Screen printing is one type of stencil printing, and is a printingmethod utilizing the mesh of a screen of fibers of e.g. silk, nylon ortetron, or a stainless steel wire. The printing method is utilized invarious fields since printing is possible even on a convex plate, a flatplate, a concave plate or a curved plate. By screen printing, it ispossible to apply the curable composition for surface protection withoutdisplacement even at a fine portion, such being preferred in view ofworkability.

In the present invention, the material of the member to be processed isnot particularly limited. The material may, for example, be a metalmember such as aluminum, iron, SUS or nickel, a glass member, a ceramicmember such as alumina or aluminum nitride, a plastic member or a wafersuch as silicon or sapphire.

The method for removing a protective film of the present invention isapplicable not only to processing of a glass lens, a plastic lens, anoptical component such as glass or quartz, or an optical disk but alsoto processing of a metal plate, a mold, an aluminum sash, a plasticplate, a semiconductor wafer, a circuit board, a ceramic, or an electricor electronic component such as a sensor.

Particularly, it is useful as a method for removing a protective filmfrom a member to be processed such as a sensor component or a circuitboard having recesses and protrusions on its surface, which should beprotected from infiltration of cutting water or scars or contaminationby e.g. cutting wastes.

Further, the present invention is useful for prevention of contaminationby a plating liquid to be used for a circuit board such as a printedwiring board, or for masking at the time of painting or printing ofvarious tablets such as nameplates or logos, scales on measuringinstruments and decorations applied to various industrial products, inaddition to electric or electronic components.

EXAMPLES

Now, the present invention will be described in further detail withreference to Examples and Comparative Examples, but it should beunderstood that the present invention is by no means restricted by suchExamples.

(Materials Used)

Materials used in Examples and Comparative Examples are exemplifiedbelow.

I-907: 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino propan-1-one(IRGACURE 907, manufactured by Ciba Specialty Chemicals)

QM: dicyclopentenyloxyethyl methacrylate (QM-657, manufactured by Rohm &Haas)

BZ: benzyl methacrylate (LIGHT-ESTER BZ, manufactured by KYOEISHACHEMICAL CO., LTD.)

IBX: isobornyl methacrylate (LIGHT-ESTER IB-X, manufactured by KYOEISHACHEMICAL CO., LTD.)

2-HEMA: 2-hydroxyethyl methacrylate

MTEGMA: methoxytetraethylene glycol monomethacrylate (NK ester M-90G,manufactured by Shin-Nakamura Chemical Corporation)

TPO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO,manufactured by BASF)

UC-203: methacryloyl-modified polyisoprene (UC-203, manufactured byKURARAY CO., LTD)

TE-2000: 1,2-polybutadiene-terminated urethane methacrylate (TE-2000,manufactured by Nippon Soda Co., Ltd., molecular weight 2,000)

UV7000B: urethane acrylate (SHIKOH UV-7000B, manufactured by NipponSynthetic Chemical Industry Co., Ltd., molecular weight 3,500)

UV3000B: polyester urethane acrylate (SHIKOH UV-3000B, manufactured byNippon Synthetic Chemical Industry Co., Ltd., molecular weight 18,000)

M-101A: phenol 2 mol ethylene oxide-modified acrylate (ARONIX M-101A,manufactured by TOAGOSEI CO., LTD.)

M-140: 2-(1,2-cyclohexacaboxyimide)ethyl acrylate (ARONIX M-140,manufactured by Toagosei Co., Ltd.)

IBXA: isobornyl acrylate (LIGHT-ACRYLATE IB-XA, manufactured by KYOEISHACHEMICAL CO., LTD.)

R-684: dicyclopentanyl diacrylate (KAYARAD R-684, manufactured by NipponKayaku Co, Ltd.)

ACMO: acryloyl morpholine (ACMO, manufactured by KOHJIN Co., Ltd.)

BDK: benzyl dimethyl ketal

MDP: 2,2-methylene-bis(4-methyl-6-tertiary butylphenol)

Quintone 1700: cyclopentadiene resin (Quintone 1700, manufactured byZEON CORPORATION)

AEROSIL R972: AEROSIL (manufactured by NIPPON AEROSIL CO., LTD.)

IPA: isopropyl alcohol

(Evaluation Methods)

Viscosity: The viscosity of a curable resin composition for surfaceprotection prepared was measured by using a Brookfield type viscometerat a temperature of 23° C.

Surface curing property: Heat resistance Pyrex (registered trademark)glass was coated with a preliminarily prepared curable resin compositionfor surface protection with a coating thickness of about 70 μm by screenprinting. Then, the composition was cured by a curing apparatus using ametal halide lamp manufactured by EYE GRAPHICS CO., LTD. under acondition of an accumulated quantity of light of 2,000 mJ/cm² at awavelength of 365 nm. Immediately after the curing, the surface curingproperty was evaluated by touching with a finger based on the followingevaluation standards.

◯: favorable without tacking

Δ: tacking a little felt

X: the composition stuck to the fingertip

Tensile shear bond strength: The strength was measured in accordancewith JIS K 6850. Specifically, heat resistant Pyrex (registeredtrademark) glass (25 mm×25 mm×2.0 mm in thickness) was used as anadherend, and two sheets of the heat resistant Pyrex (registeredtrademark) glass were bonded in a bonding area with a diameter of 8 mmwith a preliminarily prepared curable resin composition. Then, thecomposition was cured by a curing apparatus using an electrodelessdischarge lamp manufactured by Fusion UV Systems Inc., under a conditionof an accumulated quantity of light of 2,000 mJ/cm² at a wavelength of365 nm, thereby preparing a test piece for tensile shear bond strength.The test piece thus prepared was subjected to measurement of tensileshear bond strength by means of a universal testing machine at atemperature of 23° C. under a humidity of 50% at a pulling rate of 10mm/min.

Removing test (1): A preliminarily prepared curable resin compositionwas applied to heat resistant Pyrex (registered trademark) glass. Then,the curable composition was cured by a curing apparatus using anelectrodeless discharge lamp manufactured by Fusion UV Systems Inc.,under a condition of an accumulated quantity of light of 2,000 mJ/cm² ata wavelength of 365 nm, thereby preparing a test piece for the removingtest as a protective film. The obtained test piece was immersed in warmwater (80° C.) and taken out every 5 minutes, and a gummed tape(Caralyan Tape, manufactured by Denki Kagaku Kogyo Kabushiki Kaisha) asa sheet was bonded to the protective film and then removed, to measurethe period of time in which the protective film was removed from heatresistant Pyrex (registered trademark) glass.

Removing test (2): A test piece for removing test having a protectivefilm formed thereon was prepared in the same manner as in Removing test(1) except that polycarbonate was used as the adherend. The obtainedtest piece was subjected to the test in the same manner to measure theperiod of time in which the protective film was removed frompolycarbonate.

Example 1-1

20 Parts by mass of TE-2000 and 15 parts by mass of R-684, as (A)polyfunctional (meth)acrylate, 40 parts by mass of M-140 and 25 parts bymass of M-101A, as (B) polyfunctional (meth)acrylate, i.e. 100 parts bymass in total of (A) and (B), 1 part by mass of Quintone 1700 as (C) aresin having a cyclopentadiene skeleton, 10 parts by mass of BDK as (D)a photopolymerization initiator, 2 parts by mass of IPA as (E) a polarorganic solvent, and 0.1 part by mass of MDP as a polymerizationinhibitor, were blended to prepare a curable resin composition. Usingthe obtained curable resin composition, the measurement of tensile shearbond strength and removing test were carried out by the above evaluationmethods. The results are shown in Table 1-1.

Examples 1-2 to 1-21

Curable resin compositions were prepared in the same manner as inExample 1-1 except that raw materials of types as identified in Tables1-1 and 1-2 were used in compositions as identified in Tables 1-1 and1-2. The measurement of tensile shear bond strength and the removingtest were carried out in the same manner as in Example 1-1, with respectto the obtained curable resin compositions. The results are shown inTables 1-1 and 1-2.

TABLE 1-1 Ex. 1-1 1-2 1-3 1-4 1-5 1-6 1-7 1-8 1-9 1-10 1-11 Component(A) (parts by mass) TE-2000 20 20 20 20 20 20 20 20 20 20 20 R-684 15 1515 15 15 15 15 15 15 15 15 Component (B) (parts by mass) M-140 40 40 4040 40 40 40 40 40 40 40 M-101A 25 25 25 25 25 25 25 25 25 25 25Component (E) IPA (b.p. 82° C.) 2 2 2 2 2 2 2 2 2 2 2 (D)photopolymerization initiator (parts by mass) BDK 10 10 10 10 10 10 1010 10 10 10 Component (C) (parts by mass) Quintone 1700 1 5 10 20 50 0.5Quintone 1500 1 3 5 10 20 Polymerization inhibitor (parts by mass) MDP0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Adhesive strength (MPa) 14.513.7 12.2 10.4 14.0 9.9 12.0 11.9 10.5 12.8 10.1 Removal time in warmwater 20 30 22 40 44 120 39 44 79 48 75 at 80° C. (min.) Removal state*)Film Film Film Film Film Adhesive Film Film Film Film Film form formform form form residue form form form form form *)Film form: The curedadhesive composition was removed in the form of a film from the glasssurface with no adhesive residue. **)Adhesive residue: An uncuredadhesive remained on the surface of the cured product.

TABLE 1-2 Ex. 1-12 1-13 1-14 1-15 1-16 1-17 1-18 1-19 1-20 1-21Component (A) (parts by mass) TE-2000 20 20 20 20 10 10 0 0 20 35 R-68415 15 15 5 25 5 25 5 15 35 Component (B) (parts by mass) M-140 40 40 4040 40 40 40 40 40 15 QM 25 M-101A 25 15 BZ 25 35 25 45 35 55 IBX 25Component (E) (parts by mass) IPA (b.p. 82° C.) 2 2 2 2 2 2 2 2 12 2 (D)photopolymerization initiator (parts by mass) BDK 10 10 10 10 10 10 1010 10 10 Component (C) (parts by mass) Quintone 1700 20 20 20 20 20 2020 20 20 20 Polymerization inhibitor (parts by mass) MDP 0.1 0.1 0.1 0.10.1 0.1 0.1 0.1 0.1 0.1 Adhesive strength (MPa) 12.1 10.8 9.8 16.3 10.717.8 12.8 10.3 3.7 2.8 Removal time in warm water at 20 152 283 22 26 81140 290 5 12 80° C. (min.) Removal state*) Film Film Film Film Film FilmFilm Film Film Film form form form form form form form form form formAdhesive residue: An uncured adhesive remained on the surface of thecured product. Film form: The cured adhesive composition was removed inthe form of a film from the glass surface with no adhesive residue.

Comparative Examples 1-1 to 1-6

Curable resin compositions were prepared in the same manner as inExample 1-1 except that raw materials of types as identified in Table1-3 were used in compositions as identified in Table 1-3. Themeasurement of tensile shear bond strength and the removing test werecarried out in the same manner as in Example 1-1, with respect to theobtained curable resin composition. The results are shown in Table 1-3.

TABLE 1-3 Comp. Ex. 1-1 1-2 1-3 1-4 1-5 1-6 Component (A) (parts bymass) TE-2000 20 R-684 15 Component (B) (parts by mass) M-140 40 M-101A25 BZ 40 IBX 60 30 Component (E) (parts by mass) IPA 2 Other components(parts by mass) 2-HEMA 70 MTEGMA 100 70 Acryloyl morpholine 100 30 (D)photopolymerization initiator (parts by mass) BDK 10 5 1.5 1.5 TPO 2.02.0 Component (C) (parts by mass) 20 20 20 20 20 20 Polymerizationinhibitor (parts by mass) MDP 0.1 0.1 0.1 0.1 0.1 0.1 Adhesive strength(MPa) 11.9 10.5 2.0 2.0 8.4 12.3 Removal time in warm water at Not Not30 30 60 Not 80° C. (min.) removed removed removed Removal state**)Adhesive Adhesive Adhesive residue residue residue **)Adhesive residue:Glass was removed, but the cured adhesive composition remained on theglass surface.

Example 1-22

Using the curable resin composition in Example 1-1, the measurement oftensile shear bond strength and the removing test were carried out inthe same manner as in Example 1-1 except that the curable resincomposition was cured by means of a curing apparatus using anelectrodeless discharge lamp manufactured by Fusion UV Systems Inc.under different accumulated light quantities of 500, 1,000, 2,000 and4,000 mJ/cm² at a wavelength of 365 nm to prepare test pieces for theremoving test and for the measurement of tensile shear bond strength.The results are shown in Table 1-4.

Comparative Example 1-7

Using the curable resin composition in Comparative Example 1-6, themeasurement of tensile shear bond strength and the removing test werecarried out in the same manner as in Example 1-1 except that the curableresin composition was cured by means of a curing apparatus using anelectrodeless discharge lamp manufactured by Fusion UV Systems Inc.under different accumulated light quantities of 500, 1,000, 2,000 and4,000 mJ/cm² at a wavelength of 365 nm to prepare test pieces for theremoving test and for the measurement of tensile shear bond strength.The results are shown in Table 1-4.

TABLE 1-4 Resin Accumulated compo- light sition quantities No. (mJ/cm²)500 1,000 2,000 4,000 Ex. Ex. Adhesive 14.3 13.0 14.5 14.2 1-22 1-1strength (MPa) Removal 16 15 20 10 time (min) Comp. Comp. Adhesive 0 012.3 9.8 Ex. Ex. strength 1-7 1-6 (MPa) Removal — — Not Not time (min)removed removed

Examples 1-23 and 1-23

Using the curable resin compositions in Examples 1-1 and 1-7, testpieces for removing test were prepared in the same manner as in Example1-1, and removing tests were carried out by changing the temperature ofwarm water to 40° C., 50° C., 60° C. and 70° C., respectively. Theresults are shown in Table 1-5. The results show the removability at anytemperature.

TABLE 1-5 Resin Temperature composition of warm No. water (° C.) 40 5060 70 Ex. Ex. Removal 376 222 185 75 1-23 1-1 time (min) Ex. Ex. Removal192 143 90 70 1-24 1-7 time (min)

Example 2-1

20 Parts by mass of TE-2000 and 15 parts by mass of R-684, as (A)polyfunctional (meth)acrylate, 40 parts by mass of n-acryloyloxyethylhexahydrophthalimide (ARONIX M-140, manufactured by TOAGOSEI CO., LTD.,hereinafter abbreviated as “M-140”) and 25 parts by mass of M-101A, as(B) polyfunctional (meth)acrylate, i.e. 100 parts by mass in total of(A) and (B), 20 parts by mass of Quintone 1700 as (C) a resin having acyclopentadiene skeleton, 10 parts by mass of BDK as (D) aphotopolymerization initiator, 2 parts by mass of IPA as (E) polarorganic solvent, and 0.1 part by mass of MDP as a polymerizationinhibitor, were blended to prepare a curable resin composition. Usingthe obtained curable resin composition, the measurement of tensile shearbond strength, viscosity and surface curability and the removing testwere carried out by the above evaluation methods. The results are shownin Table 2-1.

Examples 2-2 to 2-10

Curable resin compositions were prepared in the same manner as inExample 2-1 except that raw materials of types as identified in Table2-1 were used in compositions as identified in Table 2-1. Themeasurement of tensile shear bond strength and the removing test werecarried out in the same manner as in Example 2-1, with respect to theobtained curable resin compositions. The results are shown in Table 2-1.

TABLE 2-1 Ex. — 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 2-9 2-10 Component (A)TE-2000 20 20 20 20 20 20 20 20 20 20 (parts by mass) R-684 15 15 15 1515 15 15 15 15 15 Component (B) M-101A 25 25 25 25 25 25 25 25 — —(parts by mass) QM — — — — — — — — 25 — BZ — — — — — — — — — 25 M140 4040 40 40 40 40 40 40 40 40 IBX — — — — — — — — — — Component (D) photo-BDK 10 10 10 10 10 — — — — — polymerization I-907 — — — — 10 10 10 10 10initiator (parts by mass) Component (C) Cyclo- 20 20 20 20 20 20 2 10 2020 (parts by mass) pentadiene resin Component (E) IPA 2 4 6 10 2 2 2 2 2Polar organic solvent 2-HEMA — — — — — — — — — — Other components MTEGMA— — — — — — — — — — (parts by mass) Acryloyl — — — — — — — — — —morpholine Polymerization MDP 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1inhibitor Adhesive strength — 10.2 14.5 11.3 8.6 5.4 15.1 12.2 13.6 15.615.4 (MPa) Removal time (min) — 15 20 8 5 1 10 13 12 30 43

Comparative Examples 2-1 to 2-5

Curable resin compositions were prepared in the same manner as inExample 2-1 except that raw materials of types as identified in Table2-1 were used in compositions as identified in Table 2-1. Themeasurement of tensile shear bond strength and the removing test werecarried out in the same manner as in Example 2-1, with respect to theobtained curable resin compositions. The results are shown in Table 2-2.

TABLE 2-2 Ex. — 2-1 2-2 2-3 2-4 2-5 Component (A) TE-2000 — — — — —(parts by mass) R-684 — — — — — Component (B) M-101A — — — — — (parts bymass) QM — — — — — BZ 40 — — — — M140 — — — — — IBX 60 — — — 30Component (D) BDK 5 1.5 1.5 2 2 photo- I-907 — — — — — polymerizationinitiator (parts by mass) Component (C) Cyclo- (parts by mass)pentadiene resin Component (E) IPA — — — — — Polar organic solvent2-HEMA — — — — 70 Other components MTEGMA — 100 — 70 — (parts by mass)Acryloyl — — 100 30 — morpholine Polymerization MDP 0.1 0.1 0.1 0. 1 0.1inhibitor Adhesive strength — 10.5 2 2 8.4 12.3 (MPa) Removal time — NotDissolved Adhesive Dissolved Not (min) removed residue removed

As a result, the protective films made of the curable resin compositionsin Comparative Examples 2-1 and 2-5 were not removed from glass.Further, the protective films made of the curable resin compositions inComparative Examples 2-2 and 2-4 were dissolved upon being brought intocontact with warm water, whereby the removing test by sheets could notbe carried out. Further, the protective film made of the curable resincomposition in Comparative Example 2-3 remained in part after theremoving test by a sheet (adhesive residue).

Examples 2-11 and 2-12

Using the curable resin compositions in Examples 2-1 and 2-5, testpieces for removing test were prepared in the same manner as in Example2-1, and removing tests were carried out by changing the temperature ofwarm water to 40° C., 50° C., 60° C. and 70° C., respectively. Theresults are shown in Table 2-3.

TABLE 2-3 Resin Temperature composition of warm No. water (° C.) 40 5060 70 Ex. Ex. Removal 40 35 22 18 2-11 2-1 time (min) Ex. Ex. Removal 2018 15 7 2-12 2-5 time (min)

Example 2-13

Using the curable resin composition in Example 2-1, a test piece forremoving test was prepared in the same manner as in Example 2-1. Then,using, as a sheet, a dicing tape (Elegrip, manufactured by Denki KagakuKogyo Kabushiki Kaisha) which is an adhesive curable with energy rays,the removing test was carried out in the same manner as in Example 2-1after irradiation with ultraviolet rays. As a result, the curable resincomposition in Example 2-1 is removed as combined with the dicing tape.

Comparative Example 2-6

Using the curable resin composition in Comparative Example 2-1, a testpiece for removing test was prepared in the same manner as in Example2-1. Then, using, as a sheet, a dicing tape (Elegrip, manufactured byDenki Kagaku Kogyo Kabushiki Kaisha) which is an adhesive curable withenergy rays, the removing test was carried out in the same manner as inExample 2-1 after irradiation with ultraviolet rays. As a result, thecurable resin composition in Comparative Example 2-1 was not removed.

Example 2-14

The curable resin composition in Example 2-1 was applied to a siliconwafer with a diameter of 6 inch, and cured in the same manner as inExample 2-1 to form a protective film. Then, the silicon wafer was fixedwith a dicing tape on the protective film side, and cut in the size of10 mm square by means of a dicing apparatus. On that occasion, nodropping of the silicon wafer occurred during cutting, and noinfiltration of cutting water was observed, thus showing goodprocessability. Then, ultraviolet rays were applied, and the cut testpieces were recovered. The protective film on every test specimen wascombined with the dicing tape, and cut test pieces without theprotective film could be recovered.

Comparative Example 2-7

The curable resin composition in Comparative Example 2-1 was applied toa silicon wafer with a diameter of 6 inch, and cured in the same manneras in Example 2-1 to form a protective film. Then, the wafer was cutinto a 10 mm square by means of a dicing apparatus in the same manner asin Example 2-14. On that occasion, dropping of the silicon waferoccurred during cutting, and the protective film was dissolved, andinfiltration of cutting water was confirmed. Then, ultraviolet rays wereapplied, and the cut test pieces were recovered. Adhesive residue of theprotective film occurred on some of test pieces.

Example 3-1

80 Parts by mass of UC-203 as (F) a (meth)acrylate having at least one(meth)acryloyl group at the terminal or in the side chain of itsmolecule and having a molecular weight of at least 500, 20 parts by massof QM as (G) a (meth)acrylate other than (F), 10 parts by mass of 1-907as (D) a photopolymerization initiator, 2 parts by mass of AEROSIL R972which is a dry method silica as (H) an inorganic filler, and 0.1 part bymass of MDP as a polymerization inhibitor, were blended to prepare acurable resin composition for surface protection. Using the obtainedcurable resin composition for surface protection, the measurement oftensile shear bond strength and the removing test were carried out bythe above evaluation methods. The results are shown in Table 3-1.

Example 3-2 to 3-19

Curable resin compositions for surface protection were prepared in thesame manner as in Example 3-1 except that raw materials of types asidentified in Tables 3-1 and 3-2 were used in compositions as identifiedin Tables 3-1 and 3-2. The measurement of tensile shear bond strengthand the removing test were carried out in the is same manner as inExample 3-1, with respect to the obtained curable resin compositions.The results are shown in Tables 3-1 and 3-2.

TABLE 3-1 Ex. — 3-1 3-2 3-3 3-4 3-5 Component (F) UC-203 80 60 90 80 —(parts by mass) TE-2000 — — — — 20 UV7000B — — — — — UV3000B — — — — —Component (G) M-101A — — — — 25 (parts by mass) QM 20 40 10 20 — BZ — —— — — M140 — — — — 40 IBXA — — — — — IBX — — — — — R-684 — — — — 15Component (D) I-907 10 10 10 10 10 photopolymerization initiator (partsby mass) Component (H) Inorganic Aerosil 2 2 2 5 filler (parts by mass)R-972 Other components 2-HEMA — — — — — (parts by mass) MTEGMA — — — — —ACMO — — — — — Cyclopentadiene resin Quintone — — — — 20 1700 Polarorganic solvent IPA — — — — 10 Polymerization inhibitor MDP 0.1 0.1 0.10.1 0.1 Viscosity (mPa · s) — 10,500 5,020 52,000 5,700 1,000 Surfacecuring property — ◯ ◯ ◯ ◯ ◯ Removability (1) (min) — 5 6 4 5 9Removability (2) (min) — 1 1 1 1 Not removed Ex. — 3-6 3-7 3-8 3-9 3-10Component (F) UC-203 — — — — — (parts by mass) TE-2000 20 — — — —UV7000B — 20 20 20 — UV3000B — — — — 20 Component (G) M-101A 25 25 25 2525 (parts by mass) QM — — — — — BZ — — — — — M140 40 40 40 40 40 IBXA —— — — — IBX — — — — — R-684 15 15 15 15 15 Component (D) I-907 10 10 1010 10 photopolymerization initiator (parts by mass) Component (H)Inorganic Aerosil 8 5 8 5 8 filler (parts by mass) R-972 Othercomponents 2-HEMA — — — — — (parts by mass) MTEGMA — — — — — ACMO — — —— — Cyclopentadiene resin Quintone 20 20 20 20 — 1700 Polar organicsolvent IPA 10 10 10 20 10 Polymerization inhibitor MDP 0.1 0.1 0.1 0.10.1 Viscosity (mPa · s) — 2,300 5,000 18,000 3,800 6,200 Surface curingproperty — ◯ ◯ ◯ ◯ ◯ Removability (1) (min) — 10 8 7 6 7 Removability(2) (min) — Not Not Not Not Not removed removed removed removed removed

TABLE 3-2 Ex. — 3-11 3-12 3-13 3-14 3-15 Component (F) UC-203 75 75 7575 75 (parts by mass) TE-2000 — — — — — UV7000B — — — — — UV3000B — — —— — Component (G) M-101A — — — — — (parts by mass) QM — — — — — BZ — — —— — M140 — — — — — IBXA 25 25 25 — 25 IBX — — — — — R-684 — — — 25 —Component (D) I-907 5 5 5 5 5 photopolymerization initiator (parts bymass) Component (H) Inorganic Aerosil — 2 5 — — filler (parts by mass)R-972 Other components 2-HEMA — — — — — (parts by mass) MTEGMA — — — — —ACMO — — 1 — 1 Cyclopentadiene resin Quintone — — — — — 1700 Polarorganic solvent IPA — — — — — Polymerization inhibitor MDP 0.1 0.1 0.10.1 0.1 Viscosity (mPa · s) — 4,080 7,200 11,300 8,600 3,900 Surfacecuring property — ◯ ◯ ◯ ◯ ◯ Removability (1) (min) — 3 5 7 13 10Removability (2) (min) — 1 1 1 7 6 Ex. — 3-16 3-17 3-18 3-19 Component(F) UC-203 75 75 75 75 (parts by mass) TE-2000 — — — — UV7000B — — — —UV3000B — — — — Component (G) M-101A — — — — (parts by mass) QM — — — —BZ — — — — M140 — — — — IBXA 25 25 25 25 IBX — — — — R-684 — — — —Component (D) I-907 5 5 5 5 photopolymerization initiator (parts bymass) Component (H) Inorganic Aerosil — — 2 5 filler (parts by mass)R-972 Other components 2-HEMA — — — — (parts by mass) MTEGMA — — — —ACMO 3 5 3 3 Cyclopentadiene resin Quintone — — — — 1700 Polar organicsolvent IPA — — — — Polymerization inhibitor MDP 0.1 0.1 0. 1 0.1Viscosity (mPa · s) — 2,800 1,600 8,200 15,600 Surface curing property —◯ ◯ ◯ ◯ Removability (1) (min) — 3 19 5 8 Removability (2) (min) — 1 202 5

Comparative Examples 3-1 to 3-5

Curable resin compositions were prepared in the same manner as inExample 3-1 except that raw materials of types as identified in Table3-3 were used in compositions as identified in Table 3-1. Themeasurement of viscosity was carried out in the same manner as inExample 3-1, with respect to the obtained curable resin compositions.

It was attempted to prepare test pieces for measurement of the surfacecuring property and for the removing test in the same manner as inExample 3-1 by screen printing. However, in each of Comparative Examples3-1 to 3-5, the viscosity was low, and screen printing could not beconducted. Thus, the curable resin composition was applied to heatresistant Pyrex (registered trademark) glass or polycarbonate as theadherend by brush coating, and measurement of the surface curingproperty and the removing test were carried out. The results are shownin Table 3-3.

TABLE 3-3 Comp. Ex. — 3-1 3-2 3-3 3-4 3-5 Component (F) UC-203 — — — — —(parts by mass) TE-2000 — — — — — UV7000B — — — — — UV3000B — — — — —Component (G) M-101A — — — — — (parts by mass) QM — — — — — BZ 40 — — —— M140 — — — — — IBXA — — — — — IBX 60 — — — 30 R-684 — — — — —Component (D) I-907 5 1.5 1.5 2 2 photopolymerization initiator (partsby mass) Component (H) Inorganic Aerosil — — — — — filler (parts bymass) R-972 Other components 2-HEMA — — — — 70 (parts by mass) MTEGMA —100 — 70 — ACMO — — 100 30 — Cyclopentadiene resin Quintone — — — — —1700 Polar organic solvent IPA — — — — — Polymerization inhibitor MDP0.1 0.1 0.1 0.1 0.1 Viscosity (mPa · s) — 30 5 15 10 17 Surface curingproperty — X X ◯ Δ X Removability (1) (min) — Not Dissolved AdhesiveDissolved Not removed residue removed Removability (2) (min) — NotDissolved Adhesive Dissolved Not removed residue removed

As a result, with each of the curable resin compositions for surfaceprotection in Examples 3-1 to 3-19, screen printing was possible, thesurface curing property was secured, and the obtained protective filmwas in the film form and easily removed.

Each of the protective films made of the curable resin compositions inComparative Examples 3-1 and 3-5 was not removed from either adherendsof glass and polycarbonate.

Further, each of the protective films made of the curable resincompositions in Comparative Examples 3-2 and 3-4 was dissolved uponbeing brought into contact with warm water. Further, the protective filmmade of the curable resin composition in Comparative Example 3-3remained in part after the removing test (adhesive residue).

INDUSTRIAL APPLICABILITY

The resin composition of the present invention has a photocurableproperty, and a cured product thereof shows a high adhesive strengthwithout being influenced by e.g. cutting water, and thus littledisplacement will occur during processing of a member to be processedand a processed member excellent in dimensional accuracy will readily beobtained. Furthermore, it loses the adhesive strength when contactedwith warm water, whereby a member can be readily recovered. Therefore,it is useful as an adhesive for temporary fixation of optical lenses,prisms, arrays, silicon wafers, semiconductor packing parts, etc.

The present invention further provides an industrially useful, simpleand environmentally excellent removing method without adhesive residue,which removes, from a member to be processed, a protective film toprotect an already processed surface or a functional portion such as acircuit or a center portion of the member to be processed frominfiltration of cutting water or from scars or contamination by e.g.cutting wastes, in processing, particularly precision processing such ascutting, grinding or polishing, of optical components or electric orelectronic components such as sensors. Still further, the presentinvention is useful as a protective film to prevent contamination bye.g. a plating liquid to be used for a circuit board such as a printedwiring board, and for masking at the time of painting or printing ofvarious tablets such as nameplates or logos, scales on measuringinstruments and decorations applied to various industrial products, inaddition to electric or electronic components.

The entire disclosures of Japanese Patent Application No. 2006-005597filed on Jan. 13, 2006, Japanese Patent Application No. 2006-248859filed on Sep. 14, 2006 and Japanese Patent Application No. 2006-281257filed on Oct. 16, 2006 including specifications, claims and summariesare incorporated herein by reference in their entireties.

1. A curable resin composition for surface protection, comprising (A) a polyfunctional (meth)acrylate, (B) a monofunctional (meth)acrylate, and (C) a resin having a cyclopentadiene skeleton.
 2. The curable resin composition according to claim 1, further comprising (D) a photopolymerization initiator.
 3. The curable resin composition according to claim 2, further comprising (E) a polar organic solvent.
 4. The curable resin composition for surface protection according to claim 1, wherein (C) has an ester group or a hydroxyl group in its molecule.
 5. A curable resin composition for surface protection, comprising (F) a (meth)acrylate having at least one (meth)acryloyl group at the terminal or in the side chain of its molecule and having a molecular weight of at least 500, (G) a (meth)acrylate other than (F), and (D) a photopolymerization initiator.
 6. The curable resin composition for surface protection according to claim 5, wherein (F) is at least one member selected from the group consisting of polybutadiene, polyisoprene, and a hydrogenated product of polybutadiene or polyisoprene.
 7. The curable resin composition for surface protection according to claim 5, further comprising (H) an inorganic filler.
 8. The curable resin composition for surface protection according to claim 7, wherein (H) is silica.
 9. The curable resin composition for surface protection according to claim 5, wherein each of (A), (B), (F) and (G) is a hydrophobic (meth)acrylate.
 10. The curable resin composition for surface protection according to claim 1, which comprises from 1 to 50 parts by mass of (A), from 5 to 95 parts by mass of (B), and from 0.1 to 50 parts by mass of (C).
 11. The curable resin composition for surface protection according to claim 2, which comprises from 1 to 50 parts by mass of (A), from 5 to 95 parts by mass of (B), from 0.1 to 50 parts by mass of (C), and from 0.1 to 20 parts by mass of (D).
 12. The curable resin composition for surface protection according to claim 3, which comprises from 1 to 50 parts by mass of (A), from 5 to 95 parts by mass of (B), from 0.1 to 50 parts by mass of (C), from 0.1 to 20 parts by mass of (D), and from 0.5 to 10 parts by mass of (E).
 13. The curable resin composition for surface protection according to claim 5, which comprises from 20 to 90 parts by mass of (F), from 10 to 80 parts by mass of (G), and from 0.1 to 20 parts by mass of (D).
 14. An adhesive comprising the curable resin composition for surface protection as defined in claim
 1. 15. A member to be processed, comprising a cured product of the curable resin composition for surface protection, as defined in claim 1, provided on its surface.
 16. A method for protecting the surface of a member to be processed, which comprises providing a protective film made of a cured product of the curable resin composition for surface protection as defined in claim 1 on the surface of the member to be processed, processing the member to be processed, and removing the protective film from the member to be processed.
 17. A method for temporarily fixing a member to be processed, which comprises bonding the member to be processed to a substrate by means of the curable resin composition for surface protection as defined in claim 1, curing the composition, processing the member to be processed, and immersing the processed member in warm water of at most 90° C., thereby to remove a cured product of the curable resin composition for surface protection.
 18. A method for removing a protective film, which comprises providing a protective film made of the curable resin composition for surface protection as defined in claim 1 on the surface of a member to be processed, processing the member to be processed, and removing the protective film from the member to be processed, wherein a sheet is bonded to the surface of the member to be processed and/or the protective film, and the member to be processed is separated from the protective film and the sheet, or the protective film is separated from the member to be processed and the sheet. 